908 EXPERIMENTAL INFECTION AND IMMUNITY 



EXPERIMENT 36. IMMUNE OPSONINS (BACTERIOTROPIN) 



1. Secure 1 c.c. of serum from a rabbit immunized with staphylococci and heat 

 0.5 c.c. at 56 C. for thirty minutes. 



2. Using the same blood and bacterial emulsion as prepared in the preceding 

 experiment, prepare two opsonic preparations with the heated and unheated immune 

 serum. 



(a) Is phagocytosis more marked than in the preceding experiment? 

 If so, why? 



(b) Is there any difference in the degree and extent of phagocytosis 

 with the heated and unheated serum? 



(c) Give the properties of immune opsonin or bacteriotropin. 



EXPERIMENT 37. HEMOPSONIN 



1. Secure 0.5 c.c. serum from a rabbit immunized with sheep cells and heat at 

 56 C. for half an hour to destroy hemolytic complement. 



2. Prepare a 5 per cent, suspension of sheep erythrocytes in normal salt solution 

 after washing them three times. 



3. Prepare an emulsion of rabbit leukocytes, or tl^e emulsion of human cells 

 in the preceding experiments may be used. 



4. Take a capillary pipet; make a mark about an inch from the tip and fit the 

 other end with a rubber teat. 



5. Draw up equal volumes of leukocytic emulsion, sheep cell suspension, and 

 serum. Mix well, seal the pipet, and inoculate for an hour at 37 C. 



6. Prepare smears and stain with Wright's blood-stain. 



(a) Has phagocytosis occurred? 



(b) Which cells have become phagocytes? 



(c) Has hemolysis occurred in the mixtures and if not, why not? 



EXERCISE J3. OPSONINS (Continued) 



EXPERIMENT 38. MECHANISM OF ACTION OF OPSONINS 



1. Secure serum from a rabbit immunized with Staphylococcus pyogenes aureus. 



2. Prepare a leukocytic suspension from normal rabbit blood. 



3. Prepare an emulsion of eighteen-hour culture of Staphylococcus aureus. 



4. Make the following mixtures in capillary pipets: 



No. 1 : Equal parts of leukocytes, serum, and bacterial emulsion. 

 No. 2: Equal parts of leukocytes and bacterial suspension. 



5. In two small test-tubes mix: 



No. 3: 0.5 c.c. each of leukocytic suspension and serum. 

 No. 4: 0.5 c.c. each of serum and bacterial emulsion. 



6. Incubate pipets 1 and 2 and tubes 3 and 4 for fifteen minutes at 37 C. 



7. Prepare smears of capillary tubes 1 and 2 and stain with carbol-thionin. 



8. To tubes 3 and 4 add 15 c.c. normal salt solution, mix, and centrifuge thor- 

 oughly. Decant off the supernatant fluid and restore volume in each tube to 1 c.c. 



9. Prepare capillary pipets as follows: 



